PH Defines how acidic or alkaline the water is. It equates to the amount
of hydrogen (H+) and hydroxide (OH-) ions are
dissolved in a solution. The more hydrogen ions there are, the more
acidic the water is and the lower the pH is. A solution that
has equal concentrations of hydroxide and hydrogen is termed neutral with
a pH value of 7. A higher concentration of
hydroxide ions would return a value above 7 or alkaline
Lake Malawi has a pH of around 8.3 (it ranges between 7.8 -8.5), it
is recommended that the pH of the aquarium water be
maintained between 7.0 and 8.5, it is wise to to attempt to match the aquarium
water with that of the lake.

Water that is poorly buffered (low KH) will be subject to higher PH fluctuations
than well-buffered water.
As a general rule, hard
water is usually alkaline (above 7) and well buffered, whereas soft water
(below 7) is usually slightly acidic and poorly buffered.
KH also has an affect on the pH.

Fluctuations in pH can be stressful and damaging to fish health also Nitrifying
bacteria, essential in the conversion of ammonia
to nitrate also have a pH range preference, which is between 7.5 and 8.6.
Variations in pH will also have an effect on some
disease treatments.

KH

Carbonate hardness or temporary hardness. Measures the buffering capacity
or the ability to absorb and neutralize added acid
without major changes to PH, the nitrogen cycle in our tanks produces nitric
acid (nitrate). If we don’t have buffering (KH), the
PH will drop over time.

GH

General hardness (GH) refers to the dissolved concentration primarily of
magnesium and calcium ions. When fish are said to
prefer ``soft'' or ``hard'' water, it is HH, not KH that is being referred
to. GH will not directly affect PH although "hard" water is
generally alkaline due to some interaction of GH and KH.

Incorrect GH will affect the transfer of nutrients and waste products through
cell membranes and can affect egg fertility, proper
functioning of internal organs such as kidneys and growth. Within
reason, most fish and plants can successfully adapt to local
GH conditions, although breeding may be impaired.

Making Changes to the Water Chemistry

Ways to raise the PH
- Place coral gravel or limestone chips in the filter as media. (these will
continually "leech" out minerals to keep the water on
the alkaline side.* This will only help and will not be enough to raise
the PH alone.)
- Use a commercial alkaline buffer
- Use common bicarbonate of soda (recommended)

Ways to increase kH:
- Adding sodium bicarbonate (baking soda). One teaspoon of baking
soda added to 50 liters of water can raise the kH of the
water by approx 4 dH without a major affect on pH.(recommended)
- Adding commercial products to increase buffering capacity

To raise KH and PH, add Bi-Carbonate of Soda. A recommendation is 1 teaspoon
per 5 (US) gallons of water (dissolve in a jug
of warm aquarium water). This can be syphoned into the tank with a
piece of airline and preferably in the strongest flow by the
filter inlet. It is important you monitor the PH throughout this process
which will mean quite a few tests. This is where a PH
monitor comes in handy so if you've got one this process is easy.
Once you reach the 0.3 increase stop, and repeat similarly on each consecutive
day until your PH reaches the required level.

Repeat this procedure for Epsom Salt, starting out with ½ teaspoon . Try
to achieve a GH between 15 and 25 dgh.

The API Liquid Test
Kits are Highly recommended for testing both KH and GH Both can be bought
together for around £6.00

The important thing to remember is consistency should be maintained when
using any of the methods used, each time water is
changed additional Epsom Salts/BiCarb should be added to buffer the new
water back up.